Cyanine dyestuffs



CYANINE DYESTUFFS Filed Nov. 15, 1963 INVENTOR OSKAR R/ES TER A TTORNEYS3,379,727 CYANINE DYESTUFFS Oskar Riester, Lever-lrusen, Germany,assignor to Agfa Aktiengesellschaft, Leverkusen, Germany, a corporationof Germany I Filed Nov. 15, 1963, Ser. No. 324,037 Claims priority,appliriztiorll 6Ggefirmany, Nov. 23, 1962,

8 Claims. (Cl.260256.5)

The invention relates to novel polymethine dyestuffs of the rhodacyaninetype and to silver halide emulsions, more especially emulsionscontaining color couplers, which are sensitized with these dyestufis.

These dyestuifs have become important as sensitizers for photographicsilver halide emulsions since they are partciularly stable with respectto other additives, particularly to color couplers. They are described,for example, in German Patents Nos. 890,249 and 921,668 or in BritishPatent No. 489,335. The class was later enlarged by the introductioninto the methine chain of substituents which bring about distinctbathochromic shifts. The sensitization curves of all these dyestuffshave, however, the disadvantage of being highly unsymmetrical: apartfrom the main maximum, there is a secondary maximum at shorterwavelength. This secondary sensitization is undesirable in colorphotography, since it impairs sharp separation of the sensitivities.This obviously applies not only to the multi-layer processes, but alsoto mixed-grain emulsions or screen processes, since selectivesensitization is always necessary for the individual regions of thespectrum. As an improvement, it has been proposed to use additionalcolor filter layers which are intended to exclude this secondarysensitivity. Apart from the difliculty of finding filter dyestuffs whichare satisfactory photographically and showthe necessary intensity andcorrect position of the absorption, an additional layer also requires aconsiderable additional technical expenditure.

The present invention has for its object to modify the rhodacyanines insuch a way that the secondary maximum disappears and the sensitizationcurve is, as far as possible, symmetrical, but the modifiedrhodacyanines are still capable of sufficient variation in order thatthe sensitization maximum can be adapted to the actual use, i.e., to theabsorption maximum of a vdyestuff image to be recorded.

It has now been found that these conditions are satisfied by dyestuffsof the following formula:

R1 wherein R represents hydrogen atoms, alkyl groups, preferably withnot more than carbon atoms, which can be substituted by carboxyl,sulphonic acid, sulphonamide or hydroxyl groups, alkcnyl groups with 2to 5 carbon atoms, such as allyl or an aralkyl group such as benzyl,which can be substituted by a sulfonic acid group; a

R represents hydrogen atoms, alkyl, advantageously having 1 to 5 carbonatoms, aralkyl or aryl radicals, such as benzyl or phenyl;

n represents 0, l or 2;

m represents 1, 2 or 3;

X represents any anion which is usual in cyanine chemisice try, such aschloride, bromide, iodide, perchlorate, thiocyanate, benzenesulfonate,p-toluene sulfonate, methylsulfate, ethylsulfate;

Y represents atoms or radicals necessary to complete a heterocyclicring, which is usual in cyanine chemistry and such rings areadvantageously oxazole, benzoxazole, thiazole, benzthiazole,thiodiazole, pyrimidine, pyrroline, benzimidazole, tetrazole, azacycloheptamethylene, selenazole or benzselenazole, naphthoxazole,oxadiazole, pyridine, pyridiazine, quinoline, triazine, thiazine,triazole, triazoline, pyrazoline or indoline;

Z represents S, 0, Se or NR whereby R represents hydrogen or an alkylradical, preferably having 1 to 5 carbon atoms.

The heterocyclic radicals can in their turn be sub stituted, forexample, by alkyl groups, with advantageously up to 6 carbon atoms,cycloalkyl, such as cyclohexyl, aralkyl, such as 'benzyl, aryl, such asphenyl, or heterocyclic radicals, such as furyl or thienyl. Furthermore,they can be substituted by radicals such as hydroxyl, lower alkoxy,amino, substituted amino, halogen, trifluoromethyl, carboxyl oresterified carboxyl. They may further be condensed with aromatic orheterocyclic rings.

Such rhodacyanines are produced by quaternising in a manner known perse, the neutrocyanines of the general Br it and reacting the resultingsalt with such heterocyclic quaternary salts which have a Af-unsaturated, cyclomethylene group in the 2-position:

H,o o-o 0% \III RI the various symbols having the meaning indicatedabove. The position of the sensitization maximum can be displaced almostas desired by varying the heterocyclic groups and so it is possible toachieve excellent adaption to the absorption of the dyestuifs images tobe reproduced from a colored original,'for example, a colored negativefilm. The dyestuffs are added to the silver halide emulsion in knownmanner, .i.e., as methanolic solutions. The quantity used is from 15 to150 mg. per gram of silver present as silver halide. The dyestuifs canalso be used mixed with one another or with other sensitizers ornonsensitizing dyestuffs. They are particularly stable with respect toother emulsion additives, such as wettingagents, stabilizers,preservatives, plasticizers or hardeners, and in fact, their sensitizingintensity can sometimes even be increased by such additives as whitetoners of the type of diaminostilbene disulphonic acid.

According to one preferred embodiment of the invention, therhodacyanines are used in emulsions containing color couplers. The colorcouplers can be incorporated into the emulsion in a solublediffusion-resistant form.

According to another method the color coupler is first dissolved in aninert high-boiling organic liquid, such as a phosphoric or aliphaticpolycarboxylic acid ester, and this solution is then dispersed in afinely divided state throughout the emulsion.

CHaSOF 718 Bxca. 675

- Sensitization f@ tn,

CiJ-C CQHE 77 Sensitization 5 maximum Brca. 690

Q GHaSOF (38.702 XI Sensitization maximum I cl tcg C N JaHs Thefollowing compounds of the present invention are examples ofrhodacyacm'ne dyes whickexhibit excellent utility:

maximum (m/u) C Has 0 4- 690 VIII a H AM 0 1w 0 he m S N b C O "m a N C0 w H 0 5 7 7. mm m mm S mu 6. H C A v s\ N w C u H. S N C C C C O a "mS N C These dyestuffs are prepared as follows:

DYESTUFF I 3 grams of 1,3-dimethyl benzimidazole-2,5-(3-ethylrhodaninine) and ml. of dimethyl sulphate are heated in an oil bath forminutes at 100 C. After cooling to 100 C., 4 g. of 2-cyc1opentenylbenzthiazole are added, and heated while stirring for 10 minutes at 80C. After cooling to C., the melt is triturated with 20 ml. of pyridine.5 ml. of triethylamine are slowly added and the mixture is heated foranother 10 minutes at 80 C. After cooling, the reaction solution istreated with ether and the ether is decanted. The dyestufi formed isdissolved in methanol and precipitated by adding potassium 'bromidesolution.

Yield: 1 gram; M.P. 268-270 C.

DYESTUFF II 1.9 grams of 1,3-dimethyl-5,6-dichlorobenzimidazole-Z,5-(3-ethyl rhodanine) are mixed with 1 gram of 2-cyclopentenylbenzthiazole and 3 grams of dimethyl sulphate and heated in an oil bathfor 5 minutes at 100 C. while stirring, the internal temperature risingto 120 C. After cooling, the melt is triturated with 20 ml. of pyridineand 2.5 ml. of triethylamine and heated for another 10 minutes at 90 C.After cooling, the reaction mass is triturated with ether and glacialacetic acid and, after decanting, the residue is formed into a pastewith 5 ml. of methanol; the dyestuif which crystallizes out issuction-filtered and washed with n-propanol.

6 Yield: 1.5 grams; M.P. 255-260 C. with decomposition. The dyestuff canbe recrystallized from methanol.

DYESTUFF III 1.7 grams of 3-methyl-4,5-benzobenzoxazole-2,5-(3'-ethyl-rhodanine) and 1.1 grams of 2-cyclohexenyl benzthiazole are heatedwith 4 ml. of dimethyl sulphate for 3 minutes at 120 C. While cooling,10 ml. of pyridine are slowly added and the mixture is heated foranother 10 minutes at 120 C. After cooling, the dyestuif isprecipitatedwith 10 ml. of 25% potassium bromide solution and thecrystals are suction-filtered and washed with propanol and ether. Thecrude dyestuif is crystallized from 300 ml. of methanol and ml. ofchloroform.

Yield: 1.3 grams; M.P. 261-262 C.

DYESTUFF IV 1.5 grams of 1-ethyl-2-methyl mercaptopyrimidine-6,5',(3'-ethyl-rhodanine) and 1.1 grams of 2-cyclopentenyl benzoxazole areheated with 4 ml. of dimethyl sulphate for 2 minutes at 120 C. Aftercooling, 10 ml. of pyridine are added, the temperature being kept below120 C. Finally, the mixture is heated for 5 minutes at 120 C. Aftercooling, the dyestuif, which has crystallized out is suctionfiltered andwashed with isopropanol.

Yield: 1.7 grams; M.P. 287291 C.

DYESTUFF V 1.5 grams of3-methyl-5-methylmercapto-1,3,4-thiodiazoline-2,5'-(3'-ethyloxazolidone-4-thione-2)and 3 grams of cyclopentenyl benzthiazole are heated with 3 ml. ofdiethyl sulphate for 5 minutes at C. After cooling, 10 ml. of pyridineare slowly added, the temperature being kept below 110 C., and then thetemperature is maintained for another 5 minutes at this level. Aftercooling, the melt is triturated with ether, the dyestuff issuctionfiltered and washed with water and n-propanol. The yield is 0.5gram. After dissolving in 100 ml. of methanol, 25 ml. of 25% potassiumiodide solution are added. The dyestuff crystallizing out issuction-filtered and washed with propanol and ether.

Yield: 0.3 gram; M.P. 252-254 C.

DYESTUFF V1 2.8 grams of 1-methylpyrrolidone-2,5'-(isopropylidene-3'-ethyl rhodanine) and 5 ml. of dimethyl sulphate are heated at 110 C.The temperature then rises to 140 C. After 5 minutes, the mixture iscooled to 100 C., 2 grams of 2-cyclopentenyl benzthiazole are added andthe whole is heated for another 10 minutes at 105 C. After cooling, 20ml. of pyridine and 3 ml. of triethylamine are added and the mixture isheated for 10 minutes at 90 C. After cooling, the dyestuff, whichcrystallizes out, is suctionfiltered and washed with n-propanol andether.

Yield: 2.3 grams; M.P. 235 C.

It is recrystallized from a mixture of 300 ml. of alcohol and 50 ml. ofmethanol.

Yield: 0.8 gram; M.P. 258-259 C.

DYESTUFF VII 1.5 grams of 3-ethyl thiazolidine-2-ethylidene-5'-(3'-ethyloxazolidone-4-thione-2) and 3 m1. of dimethyl sulphate are heatedfor 10 minutes at 80 C. After adding 1.1 grams of cyclopentenylbenzthiazole, heating is continued for another 5 minutes at C. Afteradding 20 ml. of acetic acid anhydride and 3 ml. of triethylamine,reaction is allowed to take place for 10 hours at room temperature. Thedyestuif crystallizes out. It is suctionfiltered and washed withpropanol. After recrystallization from 30 ml. of methanol, there areobtained 0.2 gram of dyestutf with an M.P. of 247 C.

DYESTUFF VIII 1.9 grams of 3-ethyl benzthiazoline-2,5'-(3-ethylselenorhodanine) and 1.1 grams of 2-cyclohexenyl benzthiazole are heatedwith 4 ml. of dimethyl sulphate for 3 minutes at 120 C. After cooling,10 ml. of pyridine and 2 ml. of triethylamine are added and the mixtureis heated for another 10 minutes at 120 C. The cooled melt is trituratedwith 30 ml. of ether. The ether is decanted and the residue, aftertrituration with 3 ml. of isopropanol, is crystallized. The crude yieldis 1.4 grams; M.P. 259 C. After recrystallization from 250 ml. ofmethanol, there are obtained 0.85 gram; M.P. 266-267 C.

DYESTUFF IX 3.2 grams of 3-ethyl benzthiazoline2,5-(3'-ethyl rhodanine)are heated with 5 ml. of dimethyl sulphate for minutes at 140 C. Inaddition, 2 grams of 2-cyclopentenyl benzthiazole are heated with 1.3grams of dimethyl sulphate at 110 C., the temperature rising to 125 C.The two quaternary salts are dissolved together in 20 ml. of pyridineand, after adding 1 ml. of triethylamine, stirred for 1 hour. Thedyestuif which crystallizes out is suction-filtered and Washed withwater until the filtrate is light-yellow. After brief flushing withn-propa- 1101, the dyestuif is dried.

Yield: l-gram; M.P. 281-283 C.

After recrystallization from a mixture of 200 ml. of methanol and 100ml. of chloroform, 0.95 gram are obtained; M.P. 291293 C.

DYESTUFF X 1.4 grams of 1,3 -dimethyl-S-trifluoromethyl-2,5'-(3'- ethylrhodanine) and 4 ml. of dirnethyl sulphate are heated for 10 minutes at160 C. After cooling to 120 C., 2 grams of 2-cyclohexenyl benzthiazoleare added and the mixture is heated for another 2 minutes at 120 C.After cooling, 10 ml. of pyridine and 1 ml. of trimethylamine are addedand the mixture is heated for minutes at 120 C. After cooling, themixture is triturated with ether, the ether is decanted off and theresidue is dissolved in 50 ml. of water. 5 ml. of 50% sodium perchloratesolution are added and the precipitated dyestuif is suction-filtered. Itis dissolved in 30 ml. of methanol and the suction is left tocrystallize. The crude yield is 0.9 g. After recrystallization from amixture of 50 ml. of chloroform and 100 ml. of methanol, there areobtained 0.4 gram; M.P. 246-25 1 C.

DYESTUFF XI 1.5 grams of 3-methyl benzthiazoline-2,5'-(1'-methyl-3'-phenyl thiohydantoin) and 2.5 ml. of dimethyl sulphate are heated for5 minutes at 140 C. and then, after cooling to 100 C., 2 grams of2-cyclopentenyl benzthiazole are added and the mixture is heated foranother 5 minutes on the steam bath. After cooling, 10 ml. of pyridineand 3 ml. of triethylamine are added and heating is continued for 10minutes at 80 C. After cooling, the mixture is triturated with ether,the ether is decanted and the dyestuif precipitated with potassiumbromide solution. The dyestuif is suction-filtered, dissolved inmethanol and, after adding 10 ml. of potassium bromide solution and ml.of water, left for crystallization. After being suction-filtered, thesubstance is Washed with water, propanol and ether.

Yield: 0.2 gram; M.P. 20l202 C.

DYESTUFF XII 1.4 grams of 3-ethyl benzthiazoline-2,5-(3'-ethylrhodanine), 1.4 grams of 2-cyclopentenyl-5-phenyl benzoxazole and 5 m1.of diethyl sulphate are heated for 10 minutes at 130 C. in an oil bath.After adding 10 ml. of n-propanol and 3 ml. of triethylamine, themixture is heated for another 10 minutes on a steam bath. After cooling,the dyestuff is precipitated with ether and the ether is decanted. Theresidue is triturated with 10 ml. of methanol and the dyestuff issuction-filtered. The dyestuff is recrystallized from 350 ml. ofmethanol. Yield 0.5 gram; M.P. 270-271 C.

8 DYESTUFF XIII 2.9 grams of 3 -hydroxyethyl-benzoxazoline-2-5'(3ethylrhodanine), 2.6 ml. of dimethylsulfate are heated together for 20minutes at 150 C., 2.0 grams of 2-cycl0- pentenylbenzselenazole and 1.3ml. of dimethylsulfate are heated together for 20 minutes at 150 C. Thetwo melts are mixed and dissolved in 5 ml. of pyridine. After adding 2ml. of triethylamine, the mixture is heated for 15 minutes at C., thecrystals which separate on cooling are sucked off and are washed withn-propanol and water. They are recrystallized from methanol-chloroform.

Yield 0.5 gram; M.P. 295 C.

DYESTUFF XIV A mixture of 1.4 grams of l-butyl-pyrrolidine-Z-S(3ethylrhodanine), 1.3 grams of 2-cyclohexenyl-benzthiazole and 2.5 ml. ofdirnethylsulfate are heated for 10 minutes at 120 C. After cooling to 80C. there are added 10 ml. of pyridine, thereafter the mixture is heatedfor 10 minutes at C. The dyestuff which has formed is precipitated withdiethylether. It is then dissolved in n-propanol and precipitated byadding an aqueous solution of sodium perchlorate. The dyestuff is suckedoff and washed with ethylacetate.

Yield: 0.4 gram; M.P. 225 C.

DYESTUFF XV A mixture of 1.6 grams ofl-(w-carboxyethyl)-pyrolidine-2-5'(3' ethylrhodanine) 1.3 grams of2-cyclopentenyl-benzthiazole and 4 ml. of dimethylsulfate are heated onthe steam bath to 100 C., whereby the reaction temperature rises to 140C. After cooling the reaction mixture has added thereto 10 m1. ofpyridine, whereby the temperature should not surpass 100 C. The reactionmixture is kept at this temperature for 5 minutes and thereafter thedyestufi is precipitated by means of ether.

Yield: 1.2 grams; M.P. 244 C.

DYESTUFF XVI A mixture of 1.9 grams of3-methyl-S-methoxy-benzselenazoline-2-5'(3 ethylrhodanine), 1.3 grams of2-cyclohexenyl-S-methylbenzoxazole and 1.5 ml. of dimethylsulfate areheated to C. for 5 minutes. The reaction mixture is cooled to 80 C. andhas added thereto 30 ml. of propanol and 3 ml. of triethylamine after 5minutes. There is added once more 2 ml. of triethylamine to the reactionmixture, whereafter the latter is kept for 5 minutes at 80 C. Thedyestufi is precipitated with ether and recrystallized from methanol.

Yield: 1.3 grams; M.P. 239-253 C.

DYESTUFF XVII A mixture of 2.1 grams of 3-(w-sulfonicacidpropyL) -5-methylmercapto thiodiazole(l,3,4) 2 5(3'-ethylrhodanine), 2.4 grams of2-cyclopentenyl-5,6-benzo-benzoxazole and 4.0 ml. of dimethylsulfate areheated for 5 minutes to 120 C. After cooling to room temperature themelt is dissolved in 10 ml. of acetic acid anhydride and 4 ml.triethylamine. After 30 minutes there are added once more 4 ml. oftriethylamine to the reaction mixture and the latter is stirred for 15minutes at 20 C. The dyestuif which crystallizes out of the reactionmixture is washed with n-propanol.

Yield: 1.5 grams, M.P. 282-284 C.

DYESTUFF XVIII A mixture of 1.3 grams ofB-methyl-S-methylmercaptothiodiazole (1,3,4,)-2-5'(3-ethylrhodanine),1.1 grams of 2 cyclopentenyl 5 methyl benzthiazole and 5 ml. ofdiethylsulfate are heated for 15 minutes to C. After cooling to 80 C.there are added 10 ml. of pyridine to the reaction mixture, whereby thetemperature rises to 130 C. The dyestuff which crystallizes duringcooling is sucked 9 off and washed with acetone. It is "recrystallizedfrom methanol and boiled out with-ethyl acetate. Yield: 2.1 grams; M.P.291- 293 C.

DYESTUFF XIX A mixture of 1.7 grams of l-methyl-aza-cycloheptylidene 2(3' allylrhodanine), 1.4 grams of 2- cyclopentenylbenzthiazole and 3 ml.of dimethylsulfate are heated for 5 minutes at 120 C. After cooling toroom temperatures the reaction mixture has added thereto ml. ofpyridine, whereby the reaction temperature should not surpass 120 C.After adding 1 ml. of triethylamine, the reaction mixture is heated for5 minutes on the steam bath. Thereafter it is cooled to roomtemperature. Then the dyestuff is precipitated with ether. It isdissolved in 5 ml. ethanol and precipitated by means of an aqueoussolution of potassium iodide. The dyestuff is recrystallized frommethanol.

Yield: 1 gram; M.P. 234 C.

DYESTUFF XX A mixture of 1.5 grams of 1-methyl-3-ethyl-tetrazoline-2-dimethine-5'-(3'-ethylrhodanine), 1.1 grams of2-cyclohexenylbenzoxazole and 5 ml. of dimethylsulfate are heated on asteam bath for 5 minutes, whereby the temperature of the reactionmixture rises to 105 C. After cooling to room temperature the reactionmixture has added thereto 5 ml. of acetic acid anhydride and 3 ml. oftriethylamine. After heating to 75 C. the mixture has added theretofurther 2 ml. of triethylamine. It is then kept for further minutes atthis temperature. The dyestuff which has formed precipitates duringcooling. It is sucked off, washed with water and n-propanol andrecrystallized from ethanol.

Yield: 1.2 grams; M.P. 236 C.

DYESTUFF XXI A mixture of 1.7 grams of 1,3,3-trimethylindolenine-2-dimethine-5'-(3'-ethylrhodanine), 1.1 grams of 2-cyclohexenylbenzoxazoleand 2 ml. of dimethylsulfate are heated for 5 minutes at 120 C. Aftercooling the reaction mixture has added thereto 10 ml. of pyridine,whereby the temperature should not surpass 100 C. The mixture is keptfor further 5 minutes at 100 C. and is then cooled to room temperature.The dyestuff which crystallizes is sucked off and washed with 'propanoland ethyl acetate.

Yield: 1.6 grams; M.P. 262-263 C.

After recrystallization from 150 ml. of ethanol the yield is 1.2 grams;M.P. 264 C.

Iclaim:

1. A cyanine dyestuif of the formula:

wherein R represents a radical of the group consisting of hydrogen,lower alkyl, lower alkenyl, lower alkyl substituted by a radical of thegroup consisting of carboxyl, sulfo, sulfonamide, hydroxy, and phenyl; Rrepresents a member selected from the group consisting of lower alkyl,lower alkyl substituted by phenyl, and phenyl; Y represents the ringmembers necessary to complete a heterocyclic ring selected from thegroup consisting of oxazole, benzoxazolc, thiazole, benzthiazole,thiodiazole, pyrimidine, pyrroline, benzimidazole, tetrazole,azocycloheptamethylene, seleriazole, bentzsele-nazole, naphlthoxazole,oxadiazole, pyridine, pyridiazine, quinoline, triazine, thiazine,triazole, triazoline, pyrazoline, and indoline; Z represents a bivalentradical of the group consisting of -S--, --O, 4eand =NR R is a.substituent of the group consisting of hydrogen and lower 10 alkyl; X'-is an anion; n is an integer from 0 to 2 and m is an integer from 1 to3.

2. A cyanine dyestufl having the formula 3. A cyanine dyestuff havingthe formula I CH3 4. A cyanine dyestuff having the formula 5. A cyaninedyestuff having the formula 6. A cyanine dyestuff having the formula I NN CH3 I A} 7. A cyanine dyestuif having the formula N C zHaS 0 4 zHs$211 8. A cyanine dyestutf having the formula 2H: CaHs (References onfollowing page) 1 12 References Cited 2,895,955 7/1959 Haseltine et a1.260-2405 UNI STATES PATENTS 2,984,664 5/1961 Fry et a1 260-24052,304,981 12/1942 Wilmanns 96-106 FOREIGN PATENTS 2,856,404 10/1958Brooker et a1. 260-240 390,249 9/1953 Germany 2,870,014 1/1959 Brookeret a1. 96-106 5 2,882,159 4/ 1959 Brooker et a1. 96-102 JOHN D.RANDOLPH, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,379,727 April 23 1968 Oskar Riester It is certified that error appears inthe above identified patent and that said Letters Patent are herebycorrected as shown below:

Columns 3 and 4, formulas I, III, VIII and XIII, the unit for"Sensitization maximum" values read "m/u" or "m/u" should read mu Column3, formula III, that portion reading "O-C" should read O=C formulas IV,VI and VII, that portion reading "CH SO each occurrence, should read CHSO formula V, right-hand portion of the formula, after "I" insert 673formula VIII, that portion reading "CH SO should read CH SO Column 4,formula X, right-hand portion of the formula, after "Cl0 insert 670formula XV, that portion reading CH CH formula XVI, right-hand portionof the formula, after "I'" insert 67D Column 5, formula XVII, thatportion reading m should read m formula XIX, right-hand portion of theformula, after "I'" insert 678 Column 10, lines 14 to 22, the formulashould appear as shown below:

0 H cs-k 2 5 \N/ N 0 I I c 11 CH3 same column 10 lines 24 to 32,left-hand portion of the formula reading C N I should read C CH3 CH3 Isame column 10 lines 35 to 43, right-hand portion of the formula reading"CH SO should read CH SO lines 54 to 63 lefthand portion of the formulareading "C-C" should read C=C Signed and sealed this 25th day ofNovember 1969 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting OfficerCommissioner of Patents

1. A CYANINE DYESTUFF OF THE FORMULA:
 3. A CYANINE DYESTUFF HAVING THEFORMULA